Coexistent Hashimoto's thyroiditis with papillary thyroid carcinoma: Impact on presentation, management, and outcome

Background. This study was performed to assess the relationship between Hashimoto's thyroiditis and the development, presentation, management, and outcome of papillary thyroid carcinoma. Methods. Two complementary analytic methods were used. The clinical study was a retrospective case-control study, including patients seen with papillary thyroid carcinoma presenting during a 12-year period. We also used a systematic literature review to identify suitable reports and meta-analysis to statistically combine published results. Results. The prevalence of Hashimoto's thyroiditis is significantly higher in patients with papillary thyroid cancer (odds ratio, 1.89; 95 % CI, 1.02-3.50). These patients typically have a dominant nodule, 44 % of which are discovered incidentally on routine examinations. Fine-needle aspiration has a sensitivity of 91 % for the identification of papillary cancer The prognostic variables at the time of a diagnosis of papillary cancer and the approach to management are not altered by the presence of coexistent Hashimoto's thyroiditis. In addition, the rate of surgical complications was not higher in patients with coexistent Hashimoto's disease, Meta-analysis suggested a positive correlation between Hashimoto's disease and disease-free survival (r = 0.09; 95 % CI, 0.05-0.12) and overall survival (r = 0.11; 95 % CI, 0.07-0.15). Conclusions. There is an increased prevalence of Hashimoto's thyroiditis in patients with papillary thyroid carcinoma. The presence of coexistent Hashimoto's thyroiditis does not affect the diagnostic evaluation or management of papillary thyroid cancers. The survival of patients who have papillary thyroid cancers may be superior in coexistent Hashimoto's thyroiditis (Surgery 1999;126:1070-7.)